Custom comparison method
A custom comparison method is programmer-defined logic that determines how values are compared according to relevant criteria rather than default identity or equality rules.
Build a Frontend Web Framework (From Scratch)
A custom comparison function is a function that determines equality according to criteria defined for the compared values rather than relying on reference identity.
- How it is used
- Guides array reconciliation when values require domain-specific equality instead of JavaScript reference identity.
- How deep it goes
- Explains the comparison hook’s role across diff operations but defers the virtual-node equality implementation.
- Examples
- Uses two structurally identical objects and an array-diff function whose equalsFn defaults to ===.
- What you can do after
- Apply it via a comparator parameter to make array-diff operations recognize domain-level equality.
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100 Go Mistakes and How to Avoid Them
A custom comparison method is programmer-defined comparison logic that checks the relevant fields or elements of values.
- How it is used
- Deploys programmer-defined equality when general deep comparison is too costly at runtime.
- How deep it goes
- Defines field checks, length checks, early returns, and element iteration, while omitting comparison-library internals.
- Examples
- Uses customer structs containing an id and operations slice, comparing matching fields and elements.
- What you can do after
- Build it from scratch by implementing field-specific equality with early exits and collection-element checks.
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Related concepts
- virtual DOMuses · A virtual DOM is an in-memory user-interface tree that frameworks compare or process to determine updates to the rendered DOM.
- reflect.DeepEqualalternative to · reflect.DeepEqual is a Go function that recursively determines whether two values, including nested and referenced values, are deeply equal.
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